The issue with this line of reasoning (although I don't principally disagree with your overall assertion) is that our presumptions surrounding each sex's respective strengths and weaknesses serve as a barrier to those that choose to defy gender expectations.
While on average, men may be better than math than woman, and on average, woman are more nurturing than men, there is going to be a subset of those groups that excel regardless of our "sex brain" (as you characterized it).
A brilliant female engineering student should not have to prove to her male colleagues that she equal to them, and conversely, a male nurse shouldn't have his patients assume that he provides a lower quality of care than his female counterpart.
People's worth (in a vocational sense) should be judged on the merits of their work. As far as I'm concerned, this is mutually exclusive of their gender, race etc.